Let me clear up a few misconceptions.
The pool heat depends on what they have the dial set to on the heater unit. It does not have any temperature markings on it, so your mileage may vary. Typically, these are locked up, so the guests cannot get to them.
The owners cannot heat the pools from 7pm-7am as someone suggests, nor are they set to run from 7am-7pm as someone else suggested. The pool heaters run by pulling heat out of the ambient air, they are heat exchanger systems. This is opposed to being fed by natural gas, propane, electricity, etc. As such, they CANNOT pull heat out of the air at night when the air temp drops below a certain threshold, that's why they don't run at night.
In contrast, the main clubhouse pool (and hot tub) is heated by propane, that's why you see a huge propane tank in the fenced off area next to the clubhouse by the fitness center. Propane can heat a pool 7x24, in any temperature.
The single most important thing you can do as a guest, is ask your owner if your rental home has a pool blanket. If they do not provide one, ask if they can. They are not very expensive, and save the owner a ton of $$ on their energy bills, they really pay for themselves very quickly. (< $75 last one I bought). Assuming the home has one, the second most important thing you can do is cover up the pool when you're not using it, especially at night.
Now, as I've walked around the resort, just as an FYI, I've seen quite a large # of the townhomes that don't have pool blankets, which is why I suggest asking.
If the pool is left uncovered at night, most of the heat will naturally escape into the atmosphere. When this happens, of course, the heater cannot turn on to heat it back up until the morning when it's warmer outside. The effect is you will have a cold pool, especially in the morning (not to mention driving the energy usage way up!).
Our kids tend to leave ours uncovered, so I'm usually out there in the evening putting it back on. It's easy to forget! And as a guest, we would not tend to know any of this, and just leave it uncovered. We notify our guests and explain to them how this works, for just this reason. A very common thing our mgmt company hears is that someone has a cold pool, when they arrive to check it out, they find the pool was left uncovered overnight. It's easily preventable!
Personally I like my splash pool super warm, so we turn the heat up and leave the cover on at all times when we're not using it! Most often, the pools will end up around 80 degrees though, but like I said, the heaters have a dial, not a temperature gauge.
When we get a sustained cold spell where it stays cold, especially without a blanket, the pools will get cold, and the heaters cannot come on. This of course, is when people start calling to complain about having cold pools to the mgmt company, when they get a sustained cold spell they know they will start getting calls, and usually it's a missing pool blanket or one not on the pool that causes the issue, besides the weather of course, that's outside of everyone's control!
